1. Field of the Invention
The present invention relates to a light-emitting device including an organic EL element.
2. Description of the Related Art
Research and development of organic EL (ElectroLuminescent) elements have been extensively conducted. The fundamental structure of the organic EL element is that a layer containing a light-emitting organic compound is sandwiched between a pair of electrodes. By applying voltage to this element, light emission from the light-emitting organic compound can be obtained.
Organic EL elements can be formed in the form of a film and thus can easily constitute large-area elements, and also have great potential as planar light sources applicable to lighting and the like.
For example, a lighting device including an organic EL element is disclosed in Patent Document 1.
In addition, as for an organic EL element, there are a top-emission type in which light is extracted from the side of a substrate, on which an organic EL element is formed; a bottom-emission type in which light is extracted from the side of the substrate, which is opposite to the side on which the organic EL element is formed; and a dual-emission type in which light is extracted from both the sides.
A conductive material having light-transmitting properties to light emitted from a light-emitting organic compound is used for an electrode on a light-emitting side in an organic EL element. For example, an oxide conductor such as an indium tin oxide or an indium zinc oxide is often used.